By Matt Audilet First-year Oklahoma head coach Brent Venables is taking some serious heat during this afternoon’s dreadful performance in the Red River Rivalry showdown. The Sooners currently trail the Longhorns 49-0 early in the fourth quarter. Venables’ squad has looked absolutely terrible on both sides of the ball, allowing nearly 600 yards of total offense and collecting under 200 of their own. With this blowout loss, Oklahoma will drop its third game in a row — bringing its overall record to 3-3 on the year. Fans and analysts around the college football world are being very critical of Ve…